This study examined the influence of preload alterations on systolic right ventricular (RV) velocities and deformation indices in patients with atrial septal defect (ASD). A total of 21 patients with ASD underwent 2-dimensional echocardiography and color Doppler myocardial imaging scan before and 24 hours after transcatheter ASD closure. The data were compared with those obtained from 30 healthy age-matched children. Longitudinal peak systolic velocities, peak systolic strain rate (SR), and end-systolic strain (epsilon) were calculated in the midsegment of the RV free wall and the septum. In patients with ASD, higher RV peak systolic velocities were recorded, which returned to normal values after closure of the defect. In contrast, RV deformation indices in the patients with ASD were not different from normal values. These RV indices did not change significantly after ASD closure. We found a significantly decreased septal function after percutaneous ASD closure. This may be attributed to the device within the atrial septum, affecting deformation of the interventricular septum. In conclusion, RV longitudinal systolic deformation indices were not significantly influenced by chronic ventricular volume overload and sudden abolishment of this volume overload. These findings suggest that SR/epsilon are relatively load-stable measures of contractile function in the clinical setting. In contrast, myocardial velocities are clearly load dependent.